As technology progresses, wireless communications devices, such as smart phones, wireless-capable computers, or the like, are becoming increasingly integrated, feature rich, and complex. Such wireless communications devices rely on semiconductor technologies, such as silicon-based technologies, which are evolving toward smaller circuit geometries, lower power consumption, higher operating speeds, and increased complexity. Complementary metal oxide semiconductor technology is an example of a silicon-based technology. Further, wireless communications devices may need to support multiple communications bands, multiple communications modes, multiple communications protocols, and the like. As such, wireless communications devices may need multiple radio frequency (RF) switches to select between different RF circuits depending on which communications bands, modes, and protocols are in use. Such complex RF systems may place strict linearity, insertion loss, and isolation demands on the RF switches.
In general, RF switches having semiconductor-based switching elements have a trade-off between insertion loss and isolation. RF switches that must handle high power levels require low insertion losses. To achieve low insertion loss and high power handling capability, the size of circuit elements within an RF switch can be relatively large. However, such large circuit elements are associated with relatively large capacitances, which decrease isolation. Further, multiple large capacitances have non-linearities, which degrade linearity of the RF switch. In particular, the performance of an RF switch is in part related to a figure of merit that is equal to the RF switch's ON state resistance RON multiplied by the RF switch's OFF state capacitance COFF. Thus, there is a need for an RF switch that improves the figure of merit and the trade-off between insertion loss and isolation and has improved linearity performance.